// Evol functions.
// Authors:
//    gumi
//    jesusalva
// Description:
//    Randomization helper functions.

// pseudo-fix randomness
// rand2( min, max )
function	script	rand2	{
    if (getargcount() == 2) {
        .@min=getarg(0)*100;
        .@max=getarg(1)*100+99;
    } else {
        .@min=0;
        .@max=getarg(0)*100-1;
    }
    return rand(.@min, .@max)/100;
}



// any(<arg>{, ...<arg>})
//     returns one argument randomly

function	script	any	{
    return getarg(rand2(getargcount()));
}



// any_of(<array>)
//     returns any member of the array

function	script	any_of	{
    return getelementofarray(getarg(0), getarrayindex(getarg(0)) + rand2(getarraysize(getarg(0)) - getarrayindex(getarg(0))));
}



// relative_array_random(<array: 0, {[value, probability]..}>)
//     returns a random entry from the array, by relative probability
//     the first key of the array should be 0 and every entries are a tuple
//     of [value, probability]

function	script	relative_array_random	{
    .@is_str = getdatatype(getarg(0)) & DATATYPE_STR;
    .@total_prob = getelementofarray(getarg(0), 0);
    .@initial_index = getarrayindex(getarg(0));
    .@initial_index = .@initial_index ? .@initial_index : 1;
    freeloop(true);

    if (.@total_prob < 1 || getarg(1, false))
    {
        // first calculation, or forced re-calculation
        .@total_prob = 0;
        .@size = getarraysize(getarg(0));

        for (.@i = .@initial_index + 1; .@i < .@size; .@i += 2) {
            if (.@is_str) {
                .@total_prob += max(1, atoi(getelementofarray(getarg(0), .@i)));
            } else {
                .@total_prob += max(1, getelementofarray(getarg(0), .@i));
            }
        }

        // we cache on the first key
        set(getelementofarray(getarg(0), 0), .@total_prob);
    }

    .@target_sum = rand2(0, .@total_prob);

    for (.@i = .@initial_index; .@sum < .@target_sum; .@i += 2) {
        if (.@is_str) {
            .@sum += atoi(getelementofarray(getarg(0), .@i + 1));
        } else {
            .@sum += getelementofarray(getarg(0), .@i + 1);
        }

        if (.@sum >= .@target_sum) {
            break;
        }
    }

    freeloop(false);
    return getelementofarray(getarg(0), .@i);
}